Commodities such as gas, water, oil and electricity are typically delivered by large transmission systems covering an extensive area. The transmission system typically includes a large array of distribution lines and various remotely located monitoring and control stations linked to a central controller by a suitable communications link. The communications link may be either in the form of a wired system or via radio frequency (RF) transmissions. The communications link is typically bi-directional allowing the remotely located stations to provide system status reports to the central controller and the central controller to direct the remotely located stations by appropriate commands.
The central controller generally prompts each remotely located station either at designated time intervals or randomly for information relating to the status of the transmission system at that location. The central controller is under computer control and typically requires a rather sophisticated arrangement of hardware and software to monitor and control a potentially large number of remotely located stations. Such systems are costly to purchase, maintain and expand upon. Moreover, the central controller is typically informed of the existence of an alarm condition and not the specific nature of the alarm. AC power must typically be provided to each remote station and easements must therefore be obtained to supply power to each remote station as well as to connect the remote stations to the central controller by wire. When RF links are used between the remote stations and the central controller, a Federal Communications Commission (FCC) license is typically required with its associated annual fees because of the high frequency of use of the communications link. Finally, when information is provided by wire between the central controller and the remote stations, each remote station must be connected to the central controller via its own discrete, dedicated signal conducting lead. This further increases the complexity and expense of the centrally controlled monitoring and control system.
The present invention addresses the aforementioned limitations of the prior art by providing a remote data collection and monitoring system for a transmission system, or distribution line, which employs a plurality of independent, computer controlled, remote logger units for monitoring the system or line and for reporting via an RF link operating characteristics, including alarms, to a central controller.